Beneficiation of garnet ores by froth flotation with water-dispersible petroleum sulfonates



Patented Oct. 7, 1947 FROTH ELOTATION WITH WATER-DIS- PERSIBLE PETROLEUM SULFONATES Robert B. Booth, Springdale, and Roy A. Pickens,

Stamford,,.Conn., assignors to American Cyanamid Company, New

tion of Maine No Drawing. Applicatio York, N. Y., corporan September 18, 1943,

1 This invention relates tothe beneflciationoi ores containing garnet.

The practical recovery of garnet from ores is quite a serious problem because the commercial uses of garnet which are mainly in the abrasive field require a high grade material. This has greatly reduced the available garnet deposits and many garnet ores have been considered unsuitable for commercial exploitation because the bene-i ,0

flciation problem up to now has proven' mountable.

According to the present invention garnets are floated away from silicate gangues such-ashamblende, serpentine, and various othe "ems; by means of water dispersible.-.su ed-petroleum hydrocarbons. Where garnet he; valuable mineral in the ore the preferred modification of the present invention includes subiecting thebre to a. treatment with an acid having a dissociation constant of at least in the conditioning step when the reagent is added. The practical beneflciation by the use of water dispersible sulfonates' of liquid petroleum hydrocarbons, which will be referred to as petroleum sulfonates, and acid is all the more surprising because in the fatty acid or soap flotation of garnetthelatter is depressed by acid as is described for example by Coghill' 8r Clemmer, Transactions of the American Institute of Mining and Metallurgical Engineers, volume 112 (1934) page 458. The preferred modification of the present invention also runs counter to the recently developed iron ore flotation processes using acid treated ore with petroleum sulfonates. In these processes which are described and claimed in the copending patents of Booth and Herkenhofl', Patent No. 2,410,376, October 29, 1946, filed April 5, 1943, and Patent No. 2,410,377, October 29, 1946, filed June 18, 1943, the flotation procedure of the present invention is applied to iron ores. It would, therefore, be assumed that the use of petroleum hydrocarbon sulfonates with 1 acid treatment would tend to float preferentially minerals containing iron. We have found-however, that in the case of the garnets it is apparently theparticular silicate type which is floated, Thus, for example, a garnet which is free from iron such as grossularite and pyrope can be floated away from iron containing gangue such as a credit-9 5 has not been determined fully. However, it would appear that the action may be bound up with the silicate structure of the garnet minerals. Other wise it wouidbe highly unlikely that silicates of such radically diflerent chemical constitution shouldfloat in the same manner. The present invention-is, therefore, not limited to any theory or the peculiar operation of the process of the present'i nventlon.

lnfmanyica-ses it isdesirable to'associate the water dispers-ible-petroleum sulfonate with an unsul'fonatedoi'lsuchas for example fuel oil. This :'-appears to be desirable in many cases but it has not been definitely determined whether the action of the unsulfonated oil is primarily one of dispersion of the sulfonate over the or particles or 7 It seems likely that both functions may be performed. Mostwater dispersible oil soluble petroleum hydrocarbon sulfonates are commercially obtained in an oil solution and, of course, this oil solutionmay be used as such. Ordinarily best results are obtained with somewhat more oil and it is, therefore, frequently desirable to add additional fuel oil. Fuel oil, for example ordinary 20 B. fuel oil, gives excellent results as an additional oiling agent and because of its low cost and ready availability constitutes the preferred addition agent from economic standpoints. However, the invention is in no, sense limited, and on the contrary other unsulfonated oils may be used, such as liquid fatty acids and the like. Among them talloel, because of its cheapness, is particularly useful. In the present case this reagent is claimed only in connection with the subject matter of the present invention, namely the beneficiation of garnet ores by froth flotation.

It is an advantage of the'present invention that the choice of acids to be used in treating the ore is quite wide. Practically any acid stronger than those having a dissociation constant of 10-" may be used, provided the acidic anion does not itself exert depressing or other undesirable effects-on garnets. Sulfuric acid gives excellent results and because of its cheapness constitutes the preferred acid. Strongly acid salts may also be used.

Dispersion of the water dispersible petroleum sulfonate is sometimes improved by using inert organic solvents such as lower paramn alcohols, and reagent mixtures containing such solvents are included in the scope of the present invention.

It is desirable to effect conditioning of the flotation feed at high solids, for example 85%,- followed by dilution to flotation pulp density,,

for which even as high as 40% solids gives excelery. There are certain special conditions, how

ever, where it is necessary to remove garnet'as an impurity in other ores and where thefg'rade of the concentrate is not of importance. llnsu'ch cases, it is possible to omit the a-cid', go'od recoveries of a lower grade concentratebeing ob- Where garnets are to be floated from .silicl'ous ganguesuch as hornblende; quartz andth'eiike, the pH of the flotation circuit is notat allcritical; howeventhe circuit should be distinctly acid having a pH below 5. This is a further advan-*- tage of the present invention. It is preferable to operate inv an acid circuit, but the exact acidity may vary over fairly wide ranges. When there is associated with the garnet very readily floatable material such as for example certain 1 iron minerals like ilmenite the separation" is somewhat more difflcult and requires careful con-' 1 trol of pH. The preferred embodiment of the present invention in which the ore is treated with lan acid in addition to the sulfonatedreagentlis necessary where garnet concentrates'oi gnom mercial grade are desired in reasonable recovtainable with the water dispersible petroleum sulfonate alone, particularly; oil-solublesulfom" lent results in efficient mechanical flotation cells. I

ated petroleum hydrocarbons; Where-the acidis obtained that equipment need not be made of 1 acid resistant material.

The flotation procedure of the present invention behaves normally with respect to slime; that is to say, in common with many anionic fiota tions it is desirable to deslime, but slime is not treatment is unnecessary the added'adv'antage associated. with a gangue containing hornblende as a principal'constituent, with smaller amounts of feldspa'r and a minoramount of quartz, was ground in a rod mill'at 67% solids to approximately the following screen size:

Per cent Weight Distribution Mesh was diluted to froth flotation density and subjected to froth flotation in Fagergren flotation machines. A rougher concentrate was obtained which was then conditioned for a short time with an additional 0.5 lb. per ton of sulfuric acid andcleaned twice for odd numbered tests and once'for even numbered tests. Where re-cleaning was effected the cleaner concentrate was conditioned with an additional 1 lb. per ton of sulfuric acid prior to re-cleaning. The following table shows the metallurgical results:

Assays per cent H Garnet Recovery p '{fgf 1%;, Reagent Tested .0 LbJton Bgh.. Final Cone. Rgh. Clean Clean Tail. :Cona Float Float 1 Float 2 1 7. 95. 4 79. 82 50 Parts SP-302 (Stanco Distrib.), 5 Parts Sec. Butyl Alcohol"; 2. 5 3. 0 I 2.-...-. 8.5 97.5 71. 97 50 Parts Calol Sodium Sultanate (Std. Oil of Calii.), 50 Parts'SP-l 2.7 3.2

. (Stance Distrib.), Parts Sec. Butyl Alcohol. 3 4; 92.2 81.56 10(1)3 Ptarltsklcalloll Sodium Sultanate (Std. Oil of Calif), 10 Parts Sec. 2.6

u y 00 o 4 6 95 83.80 fioAll argslUltranate No. 2 (Atlantic Ref. (30.), 5 Parts Sec. Butyl 2.5 2.8

' co 0 5 2 94. 5 89.06 Parts Petronate (Sonneborn Sons), 5 Parts Sec. Butyl Alcohol. 2. 5 2.8 2. 8

I'critical 'as in silica flotation operations employ- Example 2 tail in conjunction with the following specific ing cationic flotation reagents.

The invention will be described in greater de- The garnet ore of Example 1 was treated with various reagent combinations employing watersoluble sulfonated petroleum hydrocarbons assoexamples.

Example 1 Screen undersize from garnet ore from northeastern United States containing approximately ciated with unsuifonated oils. The concentrate from the firsttest was re-cleaned, the second test cleaned three times, and the others cleaned only once. Acid was used as in Example I. The metallurgical data appear in the following ta n. Green t Acids (Sonneborn Sons) 1.0

Green Snlfonic Acid Residue (20%) (Fun Oil Co.) 3.0 Lbs/Lon of 20% solution.

5'3 30 SP-702 (Stance Distrib. Inc.) 0.75

n. 07.94 SP-702 (Stance Distrib. Inc.) 0.75 Lb. on

89. l6 Green Acids (Sonncborn Sons) 1.0 ton 68.75 Green Acids (Scnncbcrn Sons) 0 ,5

(0 MP- la ((iu Punt) l.0-Lb.lt0n.

.. ..do.... No. 2 Fuel on 3.5 Lbs./ton

Talloel 0.52 L b./ton

California Crude Oil 0.50 Lb./ton

Oleic Acid 0.53 Lb./tcn. Coconut Oil 0.5 Lb./ton

22 B". Fuel Oil 1.5 Lbs-lion.

. 26% garnet principally in the form of almandite ble:

Assays per cent 2 Q 7 arnet Recov pH ig Sulfonate Tested Addition Agent Rgh.- Final Cone. Rgh. Clean. Clean. Clean 'Iall Cone. Float Float l Float2 Fl0at3 2. 5 92. 5 57. SI -70 2 (Stanco Distrib. Inc.) 1.0 22 B. Fuel Oil 0.5 LbJton... 2L 3 2. 5 2 8 It will be apparent that while a'high grade was obtained with practically all of the foregoingreagent combinations there was considerable variation in the recovery. This is typical of the present invention as it has been found that while the sulfonates are generally useful there are diflerences between various sulfonates.

Example 3 The effect of various acids in the conditionins step was determined by following the procedureof Example 1, conditioning the ore at high solids with 1 lb. per ton of 50 parts of Petronate and 5 parts of secondary butyl alcoholiusing various amounts of acid. The results appear in lowing table:

the 101- Per cent Distribution Percent Weight seas;

ssass sa s-3 Example 6 The procedure of Example ii was followed but andradite with a hornblende quartzgangue was Per cent Recov- Y Garnet in Final Cone.

Assa sper cent arnet Acid Used Rgh. Tail.

Final. Conc.

92.08 Sulfuric Hydrochloric 36%. H droiluoric 48%I N tric Boric s r-F ver.

1 All water used for flotation was saturated all rougher concentrates.

It will be apparent that when acids weaker than carbonic acid are used the grade is not satisfactory and apparently nitric acid contains an anion which adversely aflects the flotation. In this respect nitric acid behaves very differently with garnet than with iron ore. It apparently does not have any deleterious effect on iron ore flotation. The reason for this difference in behaviour has not yet been determined.

with C0: (pH 5.0).

Example 4 The procedure of Example 3 was followed sub- Onc cleaningol substitutedfor the pyrope. The metallurgical results appear in the following table:

Per cent Product Andrsdite stituting strongly acid salts for acids. The met- I aliurgical results appear in the following table:

Example 7 An ore containing :grossularite with a hornblends gangue was conditioned as in the 'preced- Assa cent per Per cent arnet LbsJton Recov- Salt Acid Salt Tested Garnet in Final Conc.

Rgh. Tail.

Final Cone.

Clean.

8 Float Float Float Sodium Silicofluoride. Sodium Ohlorosulionate. Potassium Bisuli'ate cac vi e

It will be apparent that acid salts give results practically the same as those obtained with strong acids, but much larger quantities are required.

' Example 5 ing examples using, however, .10 lbs. of sulfuric acid per ton instead of "l. "The rougher ifloat'was carried on in series with stage 'oiling of additional'2 lbs. per ton of sulfonatesreagent. C'I'i e combined rougher concentrates were then conditioried with an additional .2 Bibs. .per; ton of. sulfuric acid and a -cleaner.':fiotationcarried out.

The metallurgical results appear in the following table:

' Assay Per cent Per cent Product per cent Distribution weght Grcssuiarite Grossularite Flot. Feed 36 100.00 Comb. Rgii. Concs 41. 57 85.1 98. (i9 Rgh. Tail... 58.43 0.8 l.3l Clean. Cone 40. 06 88 98. 38 Clean. 'lail 1.51 7 0. 3i

Distribution eases 7 I 8 1 1 The metallurgical results appear in the following I I Example 8 table: v The procedure-of Example was followed with I an ore containing rhodolite-with a gangue of V Percent Garnet 1:25:53; mixed talc, biotite, quartz, hornblende and trem- 5 gggg Per mm 5 I I olite. The amount of sulfuric acid used in con- Feed g5}: 53 65 3? I .ditioning the original feed was 10 lbs. per ton I 1 and sulfonate reagent 1.77 lbs. per ton. A rough- 85 I 28 2 9M 9268 ex concentrate was obtained which was condim '21 I a 04 00.43

tioned with an additional 4 lbs. per ton of sul- I I furic acid and cleaned. .The metallurgical results It will be apparent that conditioning at high solids is not as essential in the present invention as in many other flotation operations and this is 1 appear in the following tables;

The effect of temperature in conditioning and floating was tested out by following the procedure secondary butyl alcohol. One test was effected j at.28 C. and the other at 8 C. The results appear in the following table:

It will apparent that there is considerable loss atlower temperature, although the grade is even higher. While it is difllcult to determine the Example 10 The effect of solids content in conditioniiig was determined by following the procedure of Eliample 1, using 1 lb. per ton of a mixture of 50 parts Petronate and 5 parts secondary butyl all cohol and 5 lbs. per ton sulfuric acid, followed 1 by a second conditioning with 0.5 lb. per ton of sulfuric acid. In one test the conditioning was I effected at solids, the second at 40% solids.

. I Amy Per cent an additional advantage of the .process of the Product E 523 hgdcefite n sgi mn P esent invention.

Example 11 I I I Flot.Fecd 100.00 63 A garnet ore such as used- ;in -Exaniple lwas 351%: 33;: 3f, conditioned with and without u-lfuric acid. In 74.03 sa 90.57 20 each case the conditioningw I with :1- lb. per ton I Clean-TB 2 of a reagent consisting oft-50' --of Petronate and 5 parts of secondary bntyl: lcohol. The High biotite. rougher concentrate was 'cleanedsonceg The re- Primarily and suits appear in the following table:

Per cent Lbs. ton Acid. Garnet gg fg 1 PH. We Rgh; Final (1; Rgh. Clean. Rgh. Clean. Tail Cone. Float Float Float Float 2 92.3 92.08 ntsoi 5.0 0.5 2.5 as 1.5 72.5 84.19 ..-do 2.0 0.5 5.1 I9' 70 76.59 None 7.5

I v a I Example 9 It will be apparent that while maximum relarge portion'of I a gangue mineral. 1. su

Per cent of sulfuric acid presents so I I a' I Garnet gag g 50 tages because the corrosion problem in he equip- T mughout mentisgreatlyreduced. r

R -h. Final Final Cone. Test We clam; I Tail- 1. A method of beneficiating garnet-containa ing ore which comprises subjecting the ore to 2 9m 9208 65 froth flotation in the presence of a collector con- .97 77-81 8 talning as its efiective constituent water dispersible petroleum sulfonates and an effective amount of an acid substance, the' anion of which is capable of forming an acid having a dissoci-- ation constant greater than 10-", said acid substance being substantially free from nitric acid, and the amount of the acid substance being, sufflcient to modify the flotation characteristics of the garnet particles, whereby a concentrate is obtained relatively rich in garnet and 'a tailing relatively poor in garnet. I

2. A method of beneficiating garnet-containing ore which comprises subjecting the ore to froth flotation in the presence of a collector contain-'- ing as its effective constituent oil soluble water dispersible petroleum sulfonates and an effective amount of an acid substance, the anion of which is capable of forming an acid having a dissociation constant greater than 10-", said acid substance being substantially free from nitric acid,

9 and the amount of the acid substance being sufficient to modify the flotation characteristics of the garnet particles, whereby a concentrate is obtained relatively rich in garnet and a tailing relatively poor in garnet.

3. A method of beneficiating garnet-containing ore which comprises subjecting the ore to froth flotation in the presence of a collector containing as its effective constituent water dispersible petroleum sulfonates and an effective amount of sulfuric acid, the amount of the latter being suflicient to modify the flotation characteristics of the garnet particles whereby a concentrate is obtained relatively rich in garnet and a tailing relatively poor in garnet.

4. A method of beneficiating garnet-containing ore which comprises subjecting the ore to froth flotation in the presence of a collector containing as its effective constituent oil soluble water dispersible petroleum sulfonates and an effective amount of sulfuric acid, the amount of the latter being sufficient to modify the flotation characteristics of the garnet particles whereby a concentrate is obtained relatively rich in garnet and a, tailing relatively poor in garnet.

5. A method of beneflciating garnet-contain ing ore which comprises subjecting the ore to froth flotation in the presence of a, collector containing as its effective constituent water soluble petroleum sulfonates and an effective amount of sulfuric acid, the amount of the latter being sufllcient to modify the flotation characteristics .01 the garnet particles whereby a concentrate is obtained relatively rich in garnet and a tailing relatively poor in garnet.

6. A method according to claim 1 in which the petroleum sulfonate is associated with an unsuifonated 011.

7. A method according to claim 3 in which the petroleum suifonate is associated with an unsulfonated oil.

8. A method according to claim 1 in which the sulfonated material is associated with an unsulfonated hydrocarbon oil.

9. A method of beneficiating garnet-containing ore which comprises subjecting the ore to froth flotation in the presence of a collector containing as its effective constituent water soluble petroleum sulfonates and an effective amount of an acid substance, the anion of which is capable of forming an acid having adissociation constant greater than 10-", said acid substance being substantially free from nitric acid, and the amountof'the acid substance being sumcient to modify the flotation characteristics of the garnet particles, whereby a concentrate is obtained relativehr rich in garnet and a tailing relatively poor in garnet.

ROBERT B. BOOTH. ROY A. PICK'ENS.

REFERENCES CITED des Sciences Physiques et Naturales, vol. 21, pages,

260-269 (1939). Copy in Scientific Library.) 

